INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
capítulos de libros
Horizontal Gene Transfer, Generalities and Lessons from Rhizobia.
TORRES TEJERIZO, G.; GIUSTI, M. A.; DEL PAPA M. F.; LOZANO, M. J.; DRAGHI, W. O.; JOFRE, E.; LAGARES A.; PISTORIO M
Año: 2010; p. 37 - 59
One of the evolutionary mechanisms that defy the understanding of the dynamics of bacterial genome is Horizontal Gene Transfer (HGT), which has been most recently evident with the massive sequencing of genomes. The HGT material together with the processes of transposition and recombination are the principal mechanisms that operate in prokaryote genome evolution. The acquisition of new DNA via horizontal genetic transfer can even promote speciation among bacterial lineages The HGT between bacteria is accomplished by at least three known mechanisms: transformation, transduction and conjugation. Within this context, special attention has been paid to the transfer of genetic material in bacteria via plasmid conjugation since this mechanism is considered one of most efficient means of DNA exchange among prokaryotes. In several rhizobia, bacteria that inhabit the soil in free-living conditions and associate in symbiosis with the root of legumes as nitrogen-fixing organisms, plasmid DNA could constitute a very high percentage of the genome. Conjugal transfer of rhizobial plasmids has been well documented since decades ago both for symbiotic and for cryptic plasmids or mobilizable. The wide distribution of mobile genetic elements in rhizobia makes the functional and phenotypic study of them a relevant focus of analysis to understand the mechanisms of adaptation, speciation and the genomes plasticity of soil microorganisms.